Heat exchanger, cooling device, projector, and electronic apparatus

Abstract

To provide a heat exchanger capable of improving heat transfer efficiency, a cooling device, a projector, and an electronic apparatus.SOLUTION: The heat exchanger includes a housing having an accommodation chamber surrounded by first to fourth side surfaces, a first circulation port disposed in a range from a half of a length from a center of the first side surface to the third side surface to the third side surface, a second circulation port disposed in a range from a half of a length from the center of the first side surface to the fourth side surface to the fourth side surface, a third circulation port disposed on the second side surface, first to third main flow paths extending in the accommodation chamber, and a plurality of first branch flow paths provided at a plurality of positions of the first main flow path. A dimension ratio of a length of the storage chamber along the first side surface to a length of the storage chamber along the third side surface is equal to or greater than 0.6 and equal to or less than 10.0.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to a heat exchanger, a cooling device, a projector, and an electronic device. [Background technology]

[0002] BACKGROUND ART Conventionally, a heat sink is known that has a flow path formed therein through which a coolant flows (see, for example, Patent Document 1). The heat sink described in Patent Document 1 has multiple fluid channels formed therein. The multiple fluid channels are formed to carry a coolant from an inlet to an outlet of a slab, which is a plate-like structure. The multiple fluid channels include at least two main channels and multiple bridging channels connecting the at least two main channels. Each of the bridging channels has a cross section that locally increases and locally decreases in the direction of coolant flow, i.e., from one main channel to the other, and heat exchange between the coolant and the heat sink occurs in such a bridging channel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-522144 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the heat sink described in Patent Document 1 has an increased contact area with the coolant and improves the efficiency of heat transfer to the coolant, it may not be sufficient as a cooling structure for a heat source that generates a large amount of heat. For this reason, there has been a demand for a heat exchanger configuration with improved heat transfer efficiency. [Means for solving the problem]

[0005] A heat exchanger according to a first aspect of the present disclosure includes a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect the first side surface and the second side surface, respectively, and are located opposite to each other, and an accommodation chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first flow port, through which a refrigerant can flow, located in the first side surface in a range from halfway along a length from a center of the first side surface to the third side surface to the third side surface; a second flow port, through which a refrigerant can flow, located in the first side surface in a range from halfway along a length from a center of the first side surface to the fourth side surface to the fourth side surface; a third flow port, located in the second side surface, through which a refrigerant can flow; a first main flow path that communicates with the outside of the housing via the first flow port, and that extends within the accommodation chamber along a first target side surface that is one of the first side surface and the third side surface, and that communicates with the outside of the housing via the second flow port; a second main flow path extending within the accommodating chamber along a second target side surface which is one of the first side surface and the fourth side surface; a third main flow path communicating with the outside of the housing via the third circulation port and extending within the accommodating chamber along one of the first main flow path and the second main flow path; a plurality of first tributary flow paths provided at a plurality of locations on the first main flow path and branching off from the first main flow path; a plurality of second tributary flow paths provided at a plurality of locations on the second main flow path and branching off from the second main flow path; a plurality of third tributary flow paths provided in a portion of the third main flow path on the first main flow path side and communicating with at least one first tributary flow path among the plurality of first tributary flow paths; and a plurality of fourth tributary flow paths provided in a portion of the third main flow path on the second main flow path side and communicating with at least one second tributary flow path among the plurality of second tributary flow paths, wherein a dimensional ratio of the length of the accommodating chamber along the first side surface to the length of the accommodating chamber along the third side surface is 0.6 or more and 10.0 or less.

[0006] A cooling device according to a second aspect of the present disclosure includes the heat exchanger according to the first aspect, a radiator that radiates heat received by the refrigerant in the heat exchanger, and a pump that circulates the refrigerant between the heat exchanger and the radiator.

[0007] A projector according to a third aspect of the present disclosure comprises a cooling device according to the second aspect described above, a light source, an optical modulation element that modulates light emitted from the light source, a projection optical device that projects the modulated light, and a heat receiving plate provided on one of the heat generating elements of the light source and the optical modulation element, and the heat exchanger of the cooling device is connected to the heat receiving plate in a manner that allows heat transfer.

[0008] An electronic device according to a fourth aspect of the present disclosure comprises a cooling device according to the second aspect and a heat generating element having a heat receiving plate, and the heat exchanger of the cooling device is connected to the heat receiving plate in a manner that allows heat transfer. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 3] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 5] FIG. 3 is a cross-sectional view showing the internal configuration of a heat exchanger according to a first comparative example. [Figure 6] FIG. 10 is a cross-sectional view showing the internal configuration of a heat exchanger according to Comparative Example 2. [Figure 7] 4 is a graph showing the efficiency of heat transfer to a refrigerant by the heat exchanger according to the first embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing the internal configuration of a heat exchanger according to Comparative Example 3. [Figure 9] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 10] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 11] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 12] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 13]FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 14] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 15] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 16] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 17] 4 is a graph showing the efficiency of heat transfer to a refrigerant by the heat exchanger according to the first embodiment. [Figure 18] FIG. 10 is a cross-sectional view showing the internal configuration of a heat exchanger provided in a cooling device of a projector according to a second embodiment. [Figure 19] 10 is a graph showing the efficiency of heat transfer to a refrigerant by a heat exchanger according to a second embodiment. [Figure 20] 10 is a graph showing the efficiency of heat transfer to a refrigerant by a heat exchanger according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. [Projector configuration] FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to this embodiment. The projector 1 according to this embodiment is an example of an electronic device, and is an image display device that modulates light emitted from a light source to form image light according to image information, and enlarges and projects the formed image light onto a projection surface SC such as a screen. As shown in Fig. 1, the projector 1 includes an image projection device 2 and a cooling device 3. In addition, although not shown, the projector 1 also includes a control device that controls the projector 1, a power supply device that supplies power to the electronic components of the projector 1, and an exterior housing that houses the image projection device 2, cooling device 3, control device, and power supply device.

[0011] [Configuration of image projection device] The image projection device 2 generates the image light described above and projects the generated image light. The image projection device 2 includes three light sources 21, three heat receiving plates 22, three light modulation elements 23, a color combining element 24, and a projection optical device 25. The three light sources 21 emit light that illuminates the three light modulation elements 23. The three light sources 21 include a red light source 21R, a green light source 21G, and a blue light source 21B. The red light source 21R emits red light to the red light modulation element 23R of the light modulation element 23. Green light source 21G emits green light to green light modulation element 23G of light modulation element 23. The blue light source 21B emits blue light to the blue light modulation element 23B of the light modulation element 23. In this embodiment, the red light source 21R, the green light source 21G, and the blue light source 21B are each configured by a light emitting element that emits light of the corresponding color. Examples of the light emitting element include solid-state light sources such as an LED (Light Emitting Diode) and an LD (Laser Diode). Each of the three heat receiving plates 22 is disposed at a corresponding one of the three light sources 21. That is, the three heat receiving plates 22 include a heat receiving plate 22R heat-transferably connected to the red light source 21R, a heat receiving plate 22G heat-transferably connected to the green light source 21G, and a heat receiving plate 22B heat-transferably connected to the blue light source 21B. Each heat receiving plate 22 is heat-transferably connected to a heat exchanger 4, which will be described later.

[0012] Each of the three light modulation elements 23 modulates incident light in accordance with image information input from the control device. The three light modulation elements 23 include a red light modulation element 23R, a green light modulation element 23G, and a blue light modulation element 23B. The red light modulation element 23R modulates the red light incident from the red light source 21R. The green light modulation element 23G modulates the green light incident from the green light source 21G. The blue light modulation element 23B modulates the blue light incident from the blue light source 21B. Each light modulation element 23R, 23G, 23B can be constructed by a liquid crystal light valve having a transmissive liquid crystal panel, an incident side polarizer provided on the light incident side of the transmissive liquid crystal panel, and an exit side polarizer provided on the light exit side of the transmissive liquid crystal panel.

[0013] The color combining element 24 combines the red light, green light, and blue light incident from the light modulation elements 23R, 23G, and 23B to form image light, and outputs the formed image light to the projection optical device 25. In this embodiment, the color combining element 24 is configured by a cross dichroic prism. However, the present invention is not limited to this, and the color combining element 24 can also be configured by a plurality of dichroic mirrors. The projection optical device 25 projects the image light incident from the color synthesis element 24 onto the projection surface SC. The projection optical device 25 can be configured as a lens assembly including, for example, a plurality of lenses and a lens barrel that houses the plurality of lenses.

[0014] [Cooling system configuration] The cooling device 3 cools the heat generating elements of the projector 1. The cooling device 3 includes a plurality of heat exchangers 4, a reservoir 31, a radiator 32, a pump 33, and a plurality of pipes 34, and circulates a refrigerant to cool the heat generating elements connected to the heat exchangers 4. That is, the cooling device 3 can include a heat exchanger 4A, which is one type of heat exchanger 4. The heat exchanger 4A will be described in detail later. In this embodiment, the refrigerant is a liquid refrigerant, but it may be a gas refrigerant.

[0015] The plurality of pipes 34 connect the plurality of heat exchangers 4, the reservoir 31, the radiator 32, and the pump 33 so that the refrigerant can flow therethrough, thereby forming a refrigerant circulation flow path. The plurality of pipes 34 include a first pipe 341, a second pipe 342, a third pipe 343, a fourth pipe 344, a fifth pipe 345, and a sixth pipe 346. The first pipe 341 connects the red heat exchanger 4R, among the multiple heat exchangers 4, to the reservoir 31. In this embodiment, the first pipe 341 connects a third flow port 57 (described later) of the red heat exchanger 4R to the reservoir 31. That is, the first pipe 341 circulates the refrigerant discharged from the third flow port 57 of the red heat exchanger 4R to the reservoir 31. The second pipe 342 connects the reservoir 31 and the radiator 32 . The third pipe 343 connects the radiator 32 and the pump 33 .

[0016] The fourth pipe 344 connects the pump 33 to the blue heat exchanger 4B among the multiple heat exchangers 4. In the present embodiment, the fourth pipe 344 connects the pump 33 to the first circulation port 55 and the second circulation port 56 of the blue heat exchanger 4B. That is, the fourth pipe 344 divides the refrigerant delivered from the pump 33 into two, and causes one of the two refrigerants to flow through the first circulation port 55 and the other refrigerant to flow through the second circulation port 56. The fifth pipe 345 connects the blue heat exchanger 4B and the green heat exchanger 4G among the multiple heat exchangers 4. In this embodiment, the fifth pipe 345 connects the third flow port 57 of the blue heat exchanger 4B to the first flow port 55 and the second flow port 56 of the green heat exchanger 4G. That is, the fifth pipe 345 divides the refrigerant discharged from the third flow port 57 of the blue heat exchanger 4B into two, and causes one of the two refrigerants to flow through the first flow port 55 of the green heat exchanger 4G and the other refrigerant to flow through the second flow port 56 of the green heat exchanger 4G.

[0017] The sixth pipe 346 connects the green heat exchanger 4G and the red heat exchanger 4R. In this embodiment, the sixth pipe 346 connects the third flow port 57 of the green heat exchanger 4G to the first flow port 55 and the second flow port 56 of the red heat exchanger 4R. That is, the sixth pipe 346 divides the refrigerant discharged from the third flow port 57 of the green heat exchanger 4G into two, and causes one of the two refrigerants to flow through the first flow port 55 of the red heat exchanger 4R and the other refrigerant to flow through the second flow port 56 of the red heat exchanger 4R.

[0018] The reservoir 31 is a tank that temporarily stores the refrigerant that has circulated through the plurality of heat exchangers 4. The radiator 32 cools the refrigerant flowing in from the reservoir 31. That is, the radiator 32 radiates heat received by the refrigerant in the heat exchanger 4. The radiator 32 has a plurality of fine flow paths 321 therein through which the refrigerant flows, and cools the refrigerant by receiving heat from the refrigerant in each of the fine flow paths. The refrigerant cooled by the radiator 32 flows to the pump 33 via a third pipe 343. The radiator 32 radiates the heat received from the refrigerant to a cooling gas flowing from a fan (not shown). The pump 33 circulates the refrigerant between the heat exchanger 4 and the radiator 32. The pump 33 sends the refrigerant circulating from the radiator 32 to the plurality of heat exchangers 4. In this embodiment, the pump 33 sends the refrigerant to the blue heat exchanger 4B via the fourth pipe 344.

[0019] [Heat exchanger configuration] Each of the plurality of heat exchangers 4 is a so-called cold plate, and transfers heat received from a heating element to a refrigerant flowing inside, thereby cooling the heating element. The plurality of heat exchangers 4 are connected to a heat receiving plate 22 disposed on a light source 21, which is one of the heating elements in this embodiment, so as to be able to transfer heat. The plurality of heat exchangers 4 include a red heat exchanger 4R, a green heat exchanger 4G, and a blue heat exchanger 4B. The red heat exchanger 4R is connected to the heat receiving plate 22R so as to be capable of transferring heat therethrough. The green heat exchanger 4G is connected to the heat receiving plate 22G so as to be capable of transferring heat therethrough. The blue heat exchanger 4B is connected to the heat receiving plate 22B so as to be capable of transferring heat therethrough.

[0020] [Case configuration] FIG. 2 is a cross-sectional view showing the internal configuration of heat exchanger 4. Specifically, FIG. 2 is a cross-sectional view showing the internal configuration of heat exchanger 41 of heat exchanger 4. The cross-sectional view has a first flow port 55 located at a position spaced apart from center 51C of first side surface 51 toward third side surface 53 by a distance of 1, where 1 is the distance from center 51C of first side surface 51 to third side surface 53, and a second flow port 56 located at a position spaced apart from center 51C toward fourth side surface 54 by a distance of 1, where 1 is the distance from center 51C of first side surface 51 to fourth side surface 54. In FIG. 2, for ease of viewing, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channels 622, third tributary channels 623, fourth tributary channels 624, first narrow tributary channels 631, and second narrow tributary channels 632. As shown in FIG. 2, each heat exchanger 4 includes a housing 5 formed in a substantially rectangular parallelepiped shape. The housing 5 is made of a metal such as copper having high thermal conductivity. The housing 5 has a first side surface 51, a second side surface 52, a third side surface 53, and a fourth side surface 54, and also has a flat-plate-shaped storage chamber 6 surrounded by the first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54.

[0021] The first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54 are each an outer surface of the housing 5. The first side surface 51 and the second side surface 52 are located on opposite sides to each other. The third side surface 53 and the fourth side surface 54 are located on opposite sides to each other. The third side surface 53 intersects with both the first side surface 51 and the second side surface 52. The fourth side surface 54 intersects with both the first side surface 51 and the second side surface 52.

[0022] Furthermore, the heat exchanger 4 has a first flow port 55 , a second flow port 56 , and a third flow port 57 . The first flow port 55 is disposed on the first side surface 51. The first flow port 55 is a communication port that communicates the outside of the housing 5 with the storage chamber 6 inside the housing 5. The first flow port 55 allows a refrigerant to flow through. The second flow port 56 is disposed on the first side surface 51. The second flow port 56 is a communication port that communicates between the outside of the housing 5 and the storage chamber 6 inside the housing 5. The second flow port 56 allows a refrigerant to flow through. The third flow port 57 is disposed at the center 52C of the second side surface 52. The third flow port 57 is a communication port that connects the outside of the housing 5 with the accommodation chamber 6. The third flow port 57 allows a refrigerant to flow through it.

[0023] In the following description, the three mutually orthogonal directions are referred to as the +X direction, the +Y direction, and the +Z direction. In this embodiment, the +X direction is the direction from the first side surface 51 to the second side surface 52, and the +Y direction is the direction from the fourth side surface 54 to the third side surface 53. The +Z direction is a direction orthogonal to both the +X direction and the +Y direction, and is, for example, a direction perpendicular to the paper surface on which FIG. 2 is shown. Although not shown, the direction opposite the +X direction is referred to as the -X direction, the direction opposite the +Y direction is referred to as the -Y direction, and the direction opposite the +Z direction is referred to as the -Z direction. The axis along the +X direction is referred to as the X axis, the axis along the +Y direction is referred to as the Y axis, and the axis along the +Z direction is referred to as the Z axis.

[0024] [Containment Room Configuration] When one of the first and second flow ports 55, 56, and the third flow port 57 is an inlet and the other is an outlet, the storage chamber 6 is a portion that transfers heat transferred from the heating element to the refrigerant flowing inside, thereby exchanging heat with the refrigerant. The shape of the storage chamber 6 is rectangular when viewed along the Z axis. The storage chamber 6 includes a plurality of main channels 611, 612, and 613, a plurality of tributary channels 621, 622, 623, and 624, and a plurality of narrow tributary channels 631 and 632. The plurality of main channels 611, 612, and 613, the plurality of tributary channels 621, 622, 623, and 624, and the plurality of narrow tributary channels 631 and 632 can be formed in the housing 5 by, for example, three-dimensional modeling. The storage chamber 6 having the main channels 611-613, the tributary channels 621-624, and the narrow tributary channels 631, 632 is configured to be line-symmetrical about an imaginary straight line that passes through the center 51C of the first side surface 51 and is perpendicular to the first side surface 51. In detail, the first main channel 611 and the second main channel 612 are arranged line-symmetrical about the imaginary straight line, the first tributary channel 621 and the third tributary channel 623 and the second tributary channel 622 and the fourth tributary channel 624 are arranged line-symmetrical about the imaginary straight line, and the first narrow tributary channel 631 and the second narrow tributary channel 632 are arranged line-symmetrical about the imaginary straight line.

[0025] [Configuration of multiple main channels] Each of the plurality of main flow paths 611, 612, 613 is connected to a corresponding one of the flow paths 55 to 57, and is a flow path configured to allow the refrigerant to flow therethrough. The first main flow path 611 is connected to the first circulation port 55. The first main flow path 611 extends along a first target side surface, which is one of the first side surface 51 and the third side surface 53, within the storage chamber 6. If half the length of the first side surface 51 is greater than the length of the third side surface 53, the first target side surface is the first side surface 51. If half the length of the first side surface 51 is less than the length of the third side surface 53, the first target side surface is the third side surface 53. If half the length of the first side surface 51 and the length of the third side surface 53 are equal, the first target side surface is one of the first side surface 51 and the third side surface 53. In the heat exchanger 41, since half the length of the first side surface 51 is less than the length of the third side surface 53, the first main flow path 611 extends from the first side surface 51 to the second side surface 52 within the storage chamber 6 along the third side surface 53, which is the first target side surface. In the heat exchanger 41, the first main flow path 611 extends in a substantially straight line from the first flow port 55 toward the second side surface 52 along the third side surface 53. The cross-sectional area of ​​the first main flow path 611 decreases as the first main flow path 611 approaches the second side surface 52.

[0026] The second main flow path 612 is connected to the second circulation port 56. The second main flow path 612 extends along a second target side surface, which is one of the first side surface 51 and the fourth side surface 54, within the storage chamber 6. When half the length of the first side surface 51 is greater than the length of the fourth side surface 54, the second target side surface is the first side surface 51. When half the length of the first side surface 51 is less than the length of the fourth side surface 54, the second target side surface is the fourth side surface 54. When half the length of the first side surface 51 and the length of the fourth side surface 54 are equal, the second target side surface is one of the first side surface 51 and the fourth side surface 54. In the heat exchanger 41, because half the length of the first side surface 51 is shorter than the length of the fourth side surface 54, the second main flow path 612 extends from the first side surface 51 to the second side surface 52 within the storage chamber 6 along the fourth side surface 54, which is the second target side surface. In the heat exchanger 41, the second main flow path 612 extends in a substantially straight line from the second flow port 56 toward the second side surface 52 along the fourth side surface 54. The flow path cross-sectional area of ​​the second main flow path 612 decreases as the second main flow path 612 approaches the second side surface 52.

[0027] The third main flow path 613 is connected to the third flow port 57. The third main flow path 613 extends in the storage chamber 6 along the extension direction of one of the first main flow path 611 and the second main flow path 612. In the heat exchanger 41, the third main flow path 613 extends from the third flow port 57 in the storage chamber 6 along the extension direction of the first main flow path 611, which extends along the third side surface 53. Specifically, the third main flow path 613 extends from the third flow port 57 toward the first side surface 51 through the center of the storage chamber 6 when viewed from the +Z direction. That is, the third main flow path 613 extends along the X-axis from the third flow port 57 provided in the third side surface 53 toward the first side surface 51, between the first main flow path 611 and the second main flow path 612 in the Y-axis in the storage chamber 6. Note that in the heat exchanger 41, the third main flow path 613 extends in a substantially linear manner from the third flow port 57 toward the first side surface 51. The flow path cross-sectional area of ​​the third main flow path 613 decreases as the third main flow path 613 approaches the first side surface 51.

[0028] [Multiple tributary configuration] The branch channels 621, 622, 623, and 624 are provided at multiple locations in the corresponding main channels of the main channels 611, 612, and 613, respectively, and are channels that branch off and extend from the main channels. The first branch channels 621 are provided at a plurality of locations on the first main channel 611, and extend by branching off from the first main channel 611. The cross-sectional area of ​​each of the plurality of first branch channels 621 is smaller than the cross-sectional area of ​​the first main channel 611. More specifically, the cross-sectional area of ​​each of the first branch channels 621 is smaller than the smallest cross-sectional area of ​​the first main channel 611. Each of the first branch channels 621 extends in a curved line. The second branch channels 622 are provided at a plurality of locations on the second main channel 612, and extend by branching off from the second main channel 612. The cross-sectional area of ​​each of the plurality of second branch channels 622 is smaller than the cross-sectional area of ​​the second main channel 612. More specifically, the cross-sectional area of ​​each of the second branch channels 622 is smaller than the smallest cross-sectional area of ​​the second main channel 612. Each of the second branch channels 622 extends in a curved line.

[0029] A plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side. That is, a plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side, in the +Y direction. At least one of the plurality of third tributary channels 623 communicates with at least one of the plurality of first tributary channels 621. Each of the third tributary channels 623 extends in a curved shape. A plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side. That is, a plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side, that is, in the -Y direction. At least one fourth tributary channel 624 of the plurality of fourth tributary channels 624 communicates with at least one second tributary channel 622 of the plurality of second tributary channels 622. Each fourth tributary channel 624 extends in a curved shape. The flow path cross-sectional area of ​​each third subchannel 623 is smaller than the flow path cross-sectional area of ​​the third main channel 613. More specifically, the flow path cross-sectional area of ​​each third subchannel 623 is smaller than the smallest flow path cross-sectional area in the third main channel 613. Similarly, the flow path cross-sectional area of ​​each fourth subchannel 624 is smaller than the flow path cross-sectional area of ​​the third main channel 613. More specifically, the flow path cross-sectional area of ​​each fourth subchannel 624 is smaller than the smallest flow path cross-sectional area in the third main channel 613.

[0030] [Configuration of multiple tributaries] Each of the plurality of first narrow tributary channels 631 is a mesh-like channel that directly or indirectly connects the first main channel 611 and the third main channel 613, and the channel cross-sectional area of ​​each first narrow tributary channel 631 is smaller than the channel cross-sectional area of ​​the first main channel 621 and the channel cross-sectional area of ​​the third main channel 623. The plurality of first narrow tributary channels 631 may include a narrow tributary channel that connects the first main channel 611 and the third main channel 613 or the third main channel 623, or may include a narrow tributary channel that connects the first main channel 611 and the third main channel 613 or the third main channel 623. In other words, the plurality of first narrow tributary channels 631 may include a channel that connects one first main channel 621 and one third main channel 623. There may be one first tributary channel 631 provided for one first tributary channel 621 or one third tributary channel 623, or there may be a plurality of first tributary channels 631 provided for one first tributary channel 621 or one third tributary channel 623. The first tributary channel 631 extends in a curved shape.

[0031] Each of the plurality of second narrow tributary channels 632 is a mesh-like channel that directly or indirectly connects the second main channel 612 and the third main channel 613, and the channel cross-sectional area of ​​each second narrow tributary channel 632 is smaller than the channel cross-sectional area of ​​the second main channel 622 and the channel cross-sectional area of ​​the fourth main channel 624. The plurality of second narrow tributary channels 632 may include a narrow tributary channel that connects the second main channel 612 and the third main channel 613 or the fourth main channel 624, or may include a narrow tributary channel that connects the second main channel 612 and the third main channel 613 or the fourth main channel 624. In other words, the plurality of second narrow tributary channels 632 may include a channel that connects one second main channel 622 and one fourth main channel 624. There may be one second narrow tributary channel 632 provided for each second tributary channel 622 or each fourth tributary channel 624, or there may be a plurality of second narrow tributary channels 632 provided for each second tributary channel 622 or each fourth tributary channel 624. The second narrow tributary channel 632 extends in a curved shape.

[0032] [Connection status of each flow path] The first main channel 611 does not directly communicate with the third main channel 613. The first main channel 611 communicates with the third main channel 613 via at least one of the first branch channel 621, the third branch channel 623, and the first narrow branch channel 631. The second main channel 612 does not directly communicate with the third main channel 613. The second main channel 612 communicates with the third main channel 613 via at least one of the second branch channel 622, the fourth branch channel 624, and the second narrow branch channel 632.

[0033] [Another example of the arrangement of the first and second circulation ports] The position of the first circulation port 55 in the first side surface 51 that communicates with the first main flow path 611 and the position of the second circulation port 56 in the first side surface 51 that communicates with the second main flow path 612 can be made different depending on the heat exchanger 4. In other words, the distance between the center 51C of the first side surface 51 and the first circulation port 55, and the distance between the center 51C and the second circulation port 56 can be made different depending on the heat exchanger 4.

[0034] [Heat exchanger with first and second flow ports at 0.75° positions] 3 is a cross-sectional view showing the internal configuration of heat exchanger 42, in which first circulation port 55 is disposed at 0.75 in the +Y direction from center 51C and second circulation port 56 is disposed at 0.75 in the -Y direction from center 51C, of ​​heat exchanger 4. In FIG. 3, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. For example, as shown in FIG. 3, heat exchanger 42, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In the heat exchanger 42, when the length from the center 51C of the first side surface 51 to the third side surface 53 is defined as 1, the first circulation port 55 is disposed 0.75 away from the center 51C toward the third side surface 53. Similarly, in the heat exchanger 42, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1, the second circulation port 56 is disposed 0.75 away from the center 51C toward the fourth side surface 54.

[0035] In the heat exchanger 42, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 75° with respect to a perpendicular line to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 42, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 75° with respect to a perpendicular line to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0036] [Heat exchanger with first and second flow ports at 0.5 position] 4 is a cross-sectional view showing the internal configuration of heat exchanger 43, in which first circulation port 55 is disposed at 0.5 in the +Y direction from center 51C and second circulation port 56 is disposed at 0.5 in the -Y direction from center 51C, of ​​heat exchanger 4. In FIG. 4, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. For example, as shown in FIG. 4, heat exchanger 43, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In heat exchanger 43, when the length from center 51C of first side surface 51 to third side surface 53 is defined as 1, first circulation port 55 is disposed 0.5 away from center 51C toward third side surface 53. Similarly, in heat exchanger 43, when the length from center 51C of first side surface 51 to fourth side surface 54 is defined as 1, second circulation port 56 is disposed 0.5 away from center 51C toward fourth side surface 54.

[0037] In the heat exchanger 43, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 60° with respect to a perpendicular line to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 43, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 60° with respect to a perpendicular line to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0038] In the heat exchanger 43, some of the multiple first tributary channels 621 are provided at the intersection between the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611 and communicate with the first main channel 611 again. Similarly, some of the multiple second tributary channels 622 are provided at the intersection between the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612 and communicate with the second main channel 612 again.

[0039] [Heat exchanger with first and second flow ports at 0.25 positions] Fig. 5 is a cross-sectional view showing the internal configuration of heat exchanger 44 according to Comparative Example 1. Specifically, Fig. 5 is a cross-sectional view showing the internal configuration of heat exchanger 44 in which first circulation port 55 is disposed at a position 0.25 in the +Y direction from center 51C and second circulation port 56 is disposed at a position 0.25 in the -Y direction from center 51C, of ​​heat exchanger 4. In Fig. 5, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. Heat exchanger 44, which is comparison example 1 for heat exchangers 41 to 43, has the same configuration and function as heat exchanger 41 described above, except that the positions of first circulation port 55 and second circulation port 56 on first side surface 51 are different and the extension directions of first main flow path 611 and second main flow path 612 are different, as shown in Figure 5. In the heat exchanger 44, the first flow port 55 is positioned 0.25 away from the center 51C of the first side surface 51 toward the third side surface 53, assuming that the length from the center 51C of the first side surface 51 to the third side surface 53 is 1. Similarly, in the heat exchanger 44, the second flow port 56 is positioned 0.25 away from the center 51C of the first side surface 51 toward the fourth side surface 54, assuming that the length from the center 51C of the first side surface 51 to the fourth side surface 54 is 1.

[0040] In the heat exchanger 44, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 along a line perpendicular to the first side surface 51, and then extends toward the third side surface 53 at an angle of approximately 90° with respect to the line perpendicular to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 44, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 along the perpendicular to the first side surface 51, and then extends toward the fourth side surface 54 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. In this case, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0041] In the heat exchanger 44, some of the multiple first tributary channels 621 are provided at the intersection of the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611, then further branch off and communicate with the first main channel 611 again. Similarly, some of the multiple second tributary channels 622 are provided at the intersection of the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612, then further branch off and communicate with the second main channel 612 again.

[0042] The third main flow path 613 of the heat exchanger 44 has a first partial flow path 6131 , a second partial flow path 6132 , and a third partial flow path 6133 . The first partial flow path 6131 is connected to the third flow port 57 and extends from the third flow port 57 toward the first side surface 51. The first partial flow path 6131 communicates with the outside of the storage chamber 6 via the third flow port 57. The second partial flow path 6132 extends from the first partial flow path 6131 to the first side face 51 side and the third side face 53 side. The third partial flow path 6133 extends from the first partial flow path 6131 to the first side face 51 side and to the fourth side face 54 side. In the heat exchanger 44, the third branch channel 623 is provided in the first partial channel 6131 and the second partial channel 6132, and the fourth branch channel 624 is provided in the first partial channel 6131 and the third partial channel 6133.

[0043] [Heat exchanger with first and second flow ports at position 0] FIG. 6 is a cross-sectional view showing the internal configuration of heat exchanger 45 according to Comparative Example 2. Specifically, FIG. 6 is a cross-sectional view showing the internal configuration of heat exchanger 45 in which first flow port 55 is arranged at position 0 in the +Y direction from center 51C and second flow port 56 is arranged at position 0 in the -Y direction from center 51C, among heat exchanger 4. That is, FIG. 6 is a cross-sectional view showing the internal configuration of heat exchanger 45 in which first flow port 55 and second flow port 56 are each arranged at center 51C. In FIG. 6, only some of the multiple first tributary channels 621 are denoted by reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. Heat exchanger 45, which is comparison example 2 for heat exchangers 41 to 43, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different, as shown in Figure 6. In the heat exchanger 45, when the length from the center 51C of the first side surface 51 to the third side surface 53 is defined as 1, the first flow port 55 is disposed away from the center 51C toward the third side surface 53 by a length of 0. Similarly, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1, the second flow port 56 is disposed away from the center 51C toward the fourth side surface 54 by a length of 0. That is, in the heat exchanger 45, the first flow port 55 and the second flow port 56 are disposed at the center 51C of the first side surface 51 so as to be shifted from each other along the Z axis.

[0044] In the heat exchanger 45, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and further extends toward the third side surface 53 at an angle of approximately 45° with respect to the perpendicular to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 45, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and further extends toward the fourth side surface 54 at an angle of approximately 45° with respect to the perpendicular to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. In this case, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0045] In addition, the accommodation chamber 6 of the heat exchanger 45 is provided with a junction channel 64 that extends from the first circulation port 55 and the second circulation port 56 toward the second side surface 52 and branches off from the first main channel 611 and the second main channel 612 to join the first and second main channels 611 and 612. The junction channel 64 has a larger cross-sectional area than the cross-sectional areas of the first main channel 611 and the second main channel 612. The junction channel 64 is provided with some of the multiple first tributary channels 621, some of the multiple second tributary channels 622, some of the multiple first narrow tributary channels 631, and some of the multiple second narrow tributary channels 632.

[0046] In the heat exchanger 45, some of the multiple first tributary channels 621 are provided at the intersection of the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611, then branch off again and communicate with the first main channel 611 again. Similarly, in the heat exchanger 45, some of the multiple second tributary channels 622 are provided at the intersection of the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612, then branch off again, and communicate with the second main channel 612 again. The third main flow path 613 of the heat exchanger 45 is similar to the third main flow path 613 of the heat exchanger 44 .

[0047] [Heat transfer efficiency of heat exchanger according to the positions of the first and second flow ports] FIG. 7 is a graph showing the efficiency of heat transfer to the refrigerant by heat exchangers 41 to 45 having first flow ports 55 and second flow ports 56 at different positions. Here, the efficiency of heat transfer to the refrigerant by the heat exchanger 4 changes depending on the positions of the first flow port 55 and the second flow port 56 on the first side surface 51. The inventors of the present disclosure investigated the heat transfer efficiency to the refrigerant of each of the above-described heat exchangers 41 to 45. As a result, it was found that, as shown in Fig. 7, in heat exchangers 41 to 43 in which first circulation ports 55 and second circulation ports 56 are arranged at positions that are 0.5 to 1 distance away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant is relatively high, and in heat exchangers 44 and 45 in which first circulation ports 55 and second circulation ports 56 are arranged at positions that are 0 to less than 0.5 distance away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant is relatively low. Furthermore, it was found that the heat transfer efficiency to the refrigerant of heat exchangers 41 and 42, among heat exchangers 41 to 43, in which flow ports 55 and 56 are arranged at a position that is 0.75 to 1 length away from the center 51C of the first side surface 51, is higher than the heat transfer efficiency to the refrigerant of heat exchanger 43, in which flow ports 55 and 56 are arranged at a position that is 0.5 length away from the center 51C of the first side surface 51. Furthermore, it was found that among the heat transfer efficiencies of the heat exchangers 41 to 45, the heat transfer efficiency of the heat exchanger 42, in which the flow ports 55, 56 are located at a distance of 0.75 mm from the center 51C of the first side surface 51, is the highest.

[0048] For this reason, it is preferable to employ, for the cooling device 3, any of the heat exchangers 41 to 43 having a first flow port 55 disposed at a distance of 0.5 to 1 from the center 51C of the first side face 51 toward the third side face 53, and a second flow port 56 disposed at a distance of 0.5 to 1 from the center 51C of the first side face 51 toward the fourth side face 54, when the length from the center 51C of the first side face 51 to the fourth side face 54 is defined as 1. Furthermore, it is preferable to employ, for the cooling device 3, any of the heat exchangers 41 and 42 having a first flow port 55 disposed at a distance of 0.75 to 1 from the center 51C of the first side face 51 toward the third side face 53, and a second flow port 56 disposed at a distance of 0.75 to 1 from the center 51C of the first side face 51 toward the fourth side face 54.

[0049] [Ratio of the dimension along the first side to the dimension along the third side] The inventors of the present disclosure further verified the relationship between the dimensional ratio L2 / L1 of the length L2 along the first side surface 51 to the length L1 of the storage chamber 6 along the third side surface 53, and the efficiency of heat transfer to the refrigerant by the heat exchanger 4. Hereinafter, the dimensional ratio L2 / L1 may be abbreviated as the aspect ratio because the storage chamber 6 is configured to have a rectangular shape when viewed along the Z axis.

[0050] 8 to 16 are cross-sectional views showing the internal structure of heat exchangers 4A with different aspect ratios. Specifically, FIGS. 8 to 16 are views showing cross sections along the XY plane of heat exchangers 4A with different aspect ratios. Note that FIG. 8 is a cross-sectional view showing the internal structure of a heat exchanger 4A1 according to Comparative Example 3. The XY plane is a plane defined by the ±X directions intersecting the first side surface 51 and the ±Y directions intersecting the third side surface 53. The heat exchanger 4A is one type of heat exchanger 4, and can be part of the cooling device 3 and connected to the heat receiving plate 22 so as to be heat transferable. The heat exchanger 4A is a cold plate that can be used in the cooling device 3, and cools the heating element by transferring heat received from the heating element to a refrigerant circulating inside. As shown in FIGS. 8 to 16 , the heat exchanger 4A includes a housing 5 having a rectangular accommodation chamber 6 surrounded by a first side surface 51, a second side surface 52, a third side surface 53, and a fourth side surface 54. Similar to the heat exchanger 42, the heat exchanger 4A has a first flow port 55 positioned 0.75 times the length from the center 51C of the first side surface 51 to the third side surface 53, and a second flow port 56 positioned 0.75 times the length from the center 51C of the first side surface 51 to the fourth side surface 54, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is 1.

[0051] The heat exchangers 4A include heat exchangers 4A1, 4A2, 4A3, 4A4, 4A5, 4A6, 4A7, 4A8, and 4A9 whose aspect ratios are in the range of 0.25 or more and 15.0 or less. The aspect ratio of the heat exchanger 4A1 shown in Fig. 8 is 0.25. The heat exchanger 4A1 is a heat exchanger that serves as Comparative Example 3 for the heat exchangers 4A2 to 4A9 shown in Figs. The aspect ratio of the heat exchanger 4A2 shown in FIG. 9 is 0.60. The aspect ratio of the heat exchanger 4A3 shown in FIG. 10 is 1.00. The aspect ratio of the heat exchanger 4A4 shown in FIG. 11 is 2.24. The aspect ratio of the heat exchanger 4A5 shown in FIG. 12 is 4.00. The aspect ratio of the heat exchanger 4A6 shown in FIG. 13 is 5.00. The aspect ratio of the heat exchanger 4A7 shown in FIG. 14 is 6.00. The aspect ratio of the heat exchanger 4A8 shown in FIG. 15 is 8.00. The aspect ratio of the heat exchanger 4A9 shown in FIG. 16 is 10.00. Although not shown in the drawings, the heat exchanger 4A having an aspect ratio of 15.0 is designated as a heat exchanger 4A10.

[0052] The storage chamber 6 of the heat exchanger 4A includes a first main flow path 611, a second main flow path 612, and a third main flow path 613. Although reference numerals are omitted in the heat exchangers 4A7 to 4A9 shown in Figures 14 to 16, the storage chamber 6 includes a first branch flow path 621, a second branch flow path 622, a third branch flow path 623, and a fourth branch flow path 624, as well as a first narrow branch flow path 631 and a second narrow branch flow path 632.

[0053] In the heat exchangers 4A1 to 4A3, the dimension L2 / 2, which is half of the dimension L2 of the storage chamber 6 along the first side surface 51, is smaller than the dimension L1 of the storage chamber 6 along the third side surface 53. Therefore, the first main flow path 611 extends along the third side surface 53, which serves as the first target side surface. In the heat exchangers 4A1 to 4A3, the dimension L2 / 2, which is half of the dimension L2 of the storage chamber 6 along the first side surface 51, is smaller than the dimension of the storage chamber 6 along the fourth side surface 54. Therefore, the second main flow path 612 extends along the fourth side surface 54, which serves as the second target side surface. On the other hand, in the heat exchangers 4A4 to 4A10, the dimension L2 / 2, which is half of the dimension L2 of the storage chamber 6 along the first side surface 51, is larger than the dimension L1 of the storage chamber 6 along the third side surface 53. Therefore, the first main flow path 611 extends along the first side surface 51, which serves as the first target side surface. In the heat exchangers 4A4 to 4A10, the dimension L2 / 2, which is half of the dimension L2 of the storage chamber 6 along the first side surface 51, is larger than the dimension of the storage chamber 6 along the fourth side surface 54. Therefore, the second main flow path 612 extends along the first side surface 51, which serves as the second target side surface. Although not shown, when dimension L2 / 2, which is half of dimension L2 of storage chamber 6 along first side surface 51, is equal to dimension L1 of storage chamber 6 along third side surface 53, first main flow path 611 extends along a first target side surface, which is at least one of first side surface 51 and third side surface 53. When dimension L2 / 2, which is half of dimension L2 of storage chamber 6 along first side surface 51, is equal to dimension of storage chamber 6 along fourth side surface 54, second main flow path 612 extends along a second target side surface, which is at least one of first side surface 51 and fourth side surface 54.

[0054] In the heat exchangers 4A1 to 4A3, the third main flow path 613 extends along one of the first main flow path 611 and the second main flow path 612. More specifically, in the heat exchangers 4A1 to 4A3, the third main flow path 613 extends from the third flow port 57 toward the first side surface 51 in a direction perpendicular to the second side surface 52, and the flow path cross-sectional area of ​​the third main flow path 613 decreases toward the first side surface 51. In the heat exchangers 4A4 to 4A10, the third main flow path 613 has a first partial flow path 6131, a second partial flow path 6132, and a third partial flow path 6133. The first partial flow path 6131 extends from the third flow port 57 toward the first side surface 51 . The second partial flow path 6132 extends along the second side surface 52 from the first partial flow path 6131 toward the third side surface 53, and the third partial flow path 6133 extends along the second side surface 52 from the first partial flow path 6131 toward the fourth side surface 54. The flow path cross-sectional area of ​​each of the partial flow paths 6131, 6132, 6133 decreases with increasing distance from the third flow port 57. For example, the flow path cross-sectional area of ​​the first partial flow path 6131 decreases with increasing distance from the third flow port 57 in the extending direction.

[0055] [Heat transfer efficiency of heat exchangers according to aspect ratio] Fig. 17 is a graph showing the heat transfer efficiency to a refrigerant of heat exchangers 4A1-4A10 with different aspect ratios (dimensional ratio L2 / L1). The graph in Fig. 17 shows the heat transfer efficiency of each of the other heat exchangers 4A1-4A3 and 4A5-4A10 expressed as a percentage, assuming that the heat transfer efficiency of heat exchanger 4A4 with an aspect ratio of 2.25, which has the highest heat transfer efficiency, is 100%. The inventors of the present disclosure investigated the heat transfer efficiency of each of the heat exchangers 4A1 to 4A10 described above in order to examine the relationship between the aspect ratio and the heat transfer efficiency of the heat exchanger. Note that, in the investigation, the amount of refrigerant supplied per unit time to each heat exchanger 4A was set to be the same.

[0056] 17, it was found that the heat transfer efficiency of heat exchangers 4A2 to 4A9 with aspect ratios of 0.6 or more and 10.0 or less was relatively high, while the heat transfer efficiency of heat exchanger 4A1 with aspect ratio less than 0.6 and the heat transfer efficiency of heat exchanger 4A10 with aspect ratio greater than 10.0 were relatively low. That is, the heat transfer efficiency of each of heat exchangers 4A2 to 4A9 was higher than that of heat exchanger 4A1 and heat exchanger 4A10, which are comparative example 3. In other words, if the highest heat transfer efficiency among heat exchangers 4A1 to 4A10 is 100%, and a good heat transfer efficiency is 93%, the heat exchangers 4A with a heat transfer efficiency of 93% or higher were heat exchangers 4A2 to 4A9 with aspect ratios of 0.6 to 10.0. This indicates that the heat transfer efficiency of each of heat exchangers 4A2 to 4A9 with aspect ratios of 0.6 to 10.0 is good. For this reason, it is preferable to use any of heat exchangers 4A2 to 4A9 for cooling device 3.

[0057] The reason why the heat transfer efficiency of each of the heat exchangers 4A1 to 4A9 is so good is considered to be as follows. In the heat exchanger 4A1 having an aspect ratio of less than 0.6 and the heat exchanger 4A10 having an aspect ratio of more than 10.0, the dimensions of the main flow paths 611, 612, 613 in the direction in which they extend are large. For example, in heat exchangers 4A1 to 4A3, the first main flow path 611 extends along the third side surface 53, and the dimension of the first main flow path 611 along the third side surface 53 in heat exchanger 4A1 is larger than the dimension of the first main flow path 611 along the third side surface 53 in heat exchangers 4A2 and 4A3. For example, in heat exchangers 4A4 to 4A10, the first main flow path 611 extends along the first side surface 51, and the dimension of the first main flow path 611 along the first side surface 51 in heat exchanger 4A10 is larger than the dimension of the first main flow path 611 along the first side surface 51 in heat exchangers 4A4 to 4A9. The same applies to the second main channel 612 and the third main channel 613.

[0058] When the refrigerant flowing through the accommodation chamber 6 flows from the first flow port 55 and the second flow port 56 to the third flow port 57, if the pressure of the refrigerant supplied to the first main flow path 611 and the second main flow path 612 is low, the refrigerant stagnates in the downstream portion of each main flow path 611, 612 in the refrigerant flow direction, making it difficult to circulate the refrigerant throughout the accommodation chamber 6. On the other hand, if the pressure of the refrigerant supplied to the first main flow path 611 and the second main flow path 612 is high, the refrigerant does not easily flow from the upstream portion of each main flow path 611, 612 in the refrigerant flow direction to the first branch flow path 621, making it difficult to circulate the refrigerant throughout the accommodation chamber 6. The same applies when the refrigerant flowing through the accommodation chamber 6 flows from the third flow port 57 to the first flow port 55 and the second flow port 56. For these reasons, it is considered that the heat transfer efficiency of a heat exchanger 4A1 having an aspect ratio of less than 0.6 is low.

[0059] In contrast, in the heat exchangers 4A2-4A9 having the aspect ratio of 0.6 or more and 10.0 or less, the dimensions of the main flow paths 611, 612, 613 in the extending direction thereof can be made smaller than in the heat exchanger 4A1 having an aspect ratio of less than 0.6. This makes it easier for the heat exchangers 4A2-4A9 to circulate the refrigerant throughout the entire accommodation chamber 6. Therefore, in the heat exchangers 4A2-4A9 having an aspect ratio of 0.6 or more and 10.0 or less, the efficiency of heat transfer of heat transferred to the heat exchangers 4A2-4A9 to the refrigerant can be improved.

[0060] When the heat transfer efficiency of heat exchanger 4A4, which has an aspect ratio of 2.25, is taken as 100%, the heat transfer efficiency of heat exchangers 4A3, 4A4, and 4A5, which have aspect ratios of 1.0 to 4.0, is 95% or higher. For this reason, it is preferable to employ any one of heat exchangers 4A3, 4A4, and 4A5, which has a higher heat transfer efficiency than heat exchangers 4A2, 4A6 to 4A9, in cooling device 3.

[0061] In addition, in the heat exchangers 4A1 to 4A10, the first circulation port 55 is positioned 0.75 times the length from the center 51C of the first side surface 51 to the third side surface 53 when the length from the center 51C of the first side surface 51 to the third side surface 53 is set to 1, and the second circulation port 56 is positioned 0.75 times the length from the center 51C of the first side surface 51 to the fourth side surface 54 when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is set to 1. However, the first circulation port 55 may be positioned away from the center 51C toward the third side surface 53 by a length of 0.5 or more and 1.0 or less when the length from the center 51C of the first side surface 51 to the third side surface 53 is set to 1, and the second circulation port 56 may be positioned away from the center 51C toward the fourth side surface 54 by a length of 0.5 or more and 1.0 or less when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is set to 1. In a heat exchanger in which the flow ports 55, 56 are arranged in such positions, the relationship between the aspect ratio and the heat transfer efficiency is similar to that described above. Therefore, in a heat exchanger in which the first flow port 55 is arranged in the range from half the length from the center 51C of the first side surface 51 to the third side surface 53 and the second flow port 56 is arranged in the range from half the length from the center 51C of the first side surface 51 to the fourth side surface 54, the aspect ratio is preferably 0.6 or more and 10.0 or less. Furthermore, the aspect ratio of the heat exchanger is more preferably 1.0 or more and 4.0 or less.

[0062] [Effects of the first embodiment] The projector 1 according to the present embodiment described above has the following advantages. The projector 1 corresponds to an electronic device and includes a cooling device 3 and a light source 21 which is a heat generating element having a heat receiving plate 22. More specifically, the projector 1 includes a light source 21, a heat receiving plate 22, a light modulation element 23, a projection optical device 25, and a cooling device 3. The heat receiving plate 22 is provided on the light source 21, which is one of the heat generating elements of the light source 21 and the light modulation element 23. A heat exchanger 4A of the cooling device 3 is connected to the heat receiving plate 22 so as to be capable of transferring heat. The light modulation element 23 modulates the light emitted from the light source 21. The projection optical device 25 projects the light modulated by the light modulation element 23. The cooling device 3 includes a heat exchanger 4A, a radiator 32, and a pump 33. The radiator 32 radiates heat received by the refrigerant in the heat exchanger 4A. The pump 33 circulates the refrigerant between the heat exchanger 4A and the radiator 32.

[0063] The heat exchanger 4A includes a housing 5, a first main flow path 611, a second main flow path 612, a third main flow path 613, a first branch flow path 621, a second branch flow path 622, a third branch flow path 623, a fourth branch flow path 624, a first flow port 55, a second flow port 56, and a third flow port 57. The housing 5 has a first side surface 51, a second side surface 52, a third side surface 53, a fourth side surface 54, and a storage chamber 6. The first side surface 51 and the second side surface 52 are located opposite each other. The third side surface 53 and the fourth side surface 54 intersect the first side surface 51 and the second side surface 52, respectively, and are located opposite each other. The storage chamber 6 is surrounded by the first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54.

[0064] First circulation port 55 is arranged on first side surface 51 in a range from half the length from center 51C of first side surface 51 to third side surface 53. In other words, when the length from center 51C of first side surface 51 to third side surface 53 is defined as 1, first circulation port 55 is arranged at a position in a range from 0.5 to 1 from center 51C toward third side surface 53. A refrigerant can flow through first circulation port 55. Second flow port 56 is arranged on first side surface 51 in a range from half the length from center 51C of first side surface 51 to fourth side surface 54. In other words, when the length from center 51C of first side surface 51 to fourth side surface 54 is defined as 1, second flow port 56 is arranged at a position in the range of 0.5 to 1 from center 51C toward fourth side surface 54. A refrigerant can flow through second flow port 56. The third flow port 57 is disposed on the second side surface. The third flow port 57 allows the refrigerant to flow through.

[0065] The first main flow path 611 communicates with the outside of the housing 5 via the first circulation port 55. The first main flow path 611 extends within the storage chamber 6 along a first target side surface, which is one of the first side surface 51 and the third side surface 53. The second main flow path 612 communicates with the outside of the housing 5 via the second flow port 56. The second main flow path 612 extends within the storage chamber 6 along a second target side surface, which is one of the first side surface 51 and the fourth side surface 54. The third main flow path 613 communicates with the outside of the housing 5 via the third flow port 57. The third main flow path 613 extends along one of the first main flow path 611 and the second main flow path 612 within the storage chamber 6.

[0066] The first branch channels 621 are provided at a plurality of locations on the first main channel 611. Each of the plurality of first branch channels 621 branches off from the first main channel 611. The second branch channels 622 are provided at a plurality of locations on the second main channel 612. Each of the plurality of second branch channels 622 branches off from the second main channel 612. A plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side. At least one of the plurality of third tributary channels 623 communicates with at least one of the plurality of first tributary channels 621. A plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side. At least one of the plurality of fourth tributary channels 624 communicates with at least one of the plurality of second tributary channels 622. In the heat exchangers 4A2 to 4A9, when the length of the storage chamber 6 along the third side surface 53 is length L1 and the length of the storage chamber 6 along the first side surface 51 is length L2, the dimensional ratio L2 / L1 of the heat exchangers 4A2 to 4A9 is 0.6 or more and 10.0 or less.

[0067] According to this configuration, the first circulation port 55 is arranged on the first side surface 51 in a range from half the length from the center 51C of the first side surface 51 to the third side surface 53, and the second circulation port 56 is arranged on the first side surface 51 in a range from half the length from the center 51C of the first side surface 51 to the fourth side surface 54. This makes it possible to improve the efficiency of heat transfer to the refrigerant by the heat exchanger 4A, as shown by the results of testing by the inventors of the present disclosure. Furthermore, in the heat exchangers 4A2 to 4A9 among the heat exchangers 4A, the dimensional ratio L2 / L1 of the length L2 of the storage chamber 6 along the first side surface 51 to the length L1 of the storage chamber 6 along the third side surface 53 is 0.6 or more and 10.0 or less. This makes it possible to increase the efficiency of heat transfer to the refrigerant compared to when the dimensional ratio L2 / L1 is less than 0.6 or exceeds 10.0. Therefore, the heat exchangers 4A2 to 4A9 can be configured with high efficiency of heat transfer to the refrigerant. Furthermore, the cooling device 3 including the heat exchangers 4A2 to 4A9 can be configured as a cooling device with high cooling efficiency for heat-generating elements. This increases the cooling efficiency for the light source 21, so that even if the amount of light incident from the light source 21 to the light modulation element 23 is increased, the temperature rise of the light source 21 can be suppressed, making it possible to configure a projector 1 that can project high-brightness image light. In other words, since the cooling efficiency for heat-generating elements can be increased, it is possible to configure an electronic device that can operate stably.

[0068] In the heat exchangers 4A3, 4A4, and 4A5 of the heat exchanger 4A, the dimensional ratio L2 / L1 of the length L2 of the first side surface 51 to the length L1 along the third side surface 53 of the accommodation chamber 6 is 1.0 or more and 4.0 or less. This configuration not only makes it easier to efficiently circulate the refrigerant throughout the entire accommodation chamber 6, but also further reduces pressure loss of the refrigerant, thereby further improving the efficiency of heat transfer to the refrigerant by the heat exchangers 4A3, 4A4, and 4A5.

[0069] In the heat exchangers 4A2 to 4A9, the accommodation chamber 6 is configured to have a rectangular shape when viewed from the ±Z direction perpendicular to both the ±X direction perpendicular to the first side surface 51 and the ±Y direction perpendicular to the third side surface 53. The ±X direction corresponds to the first direction, the ±Y direction corresponds to the second direction, and the ±Z direction corresponds to the third direction. This configuration allows the refrigerant to easily flow from one of the first and second circulation ports 55, 56, and the third circulation port 57 to the other, while distributing the refrigerant throughout the accommodation chamber 6. This further improves the efficiency of heat transfer to the refrigerant by the heat exchangers 4A2 to 4A9.

[0070] In the heat exchangers 4A2 to 4A9, the accommodation chambers 6 are configured to be line-symmetrical with respect to an imaginary line that passes through the center 51C of the first side surface 51 and is perpendicular to the first side surface 51. According to this configuration, the design of the accommodation chamber 6 in which the flow paths 611 to 613, 621 to 624, 631, and 632 are provided, and further the design of the heat exchangers 4A2 to 4A9, can be simplified.

[0071] In the heat exchangers 4A2 to 4A9, the flow path cross-sectional area of ​​the first branch flow path 621 is smaller than the flow path cross-sectional area of ​​the first main flow path 611. The flow path cross-sectional area of ​​the second branch flow path 622 is smaller than the flow path cross-sectional area of ​​the second main flow path 612. The flow path cross-sectional areas of the third branch flow path 623 and the fourth branch flow path 624 are each smaller than the flow path cross-sectional area of ​​the third main flow path 613. With this configuration, a larger number of first tributary channels 621 can be provided in first main channel 611, and a larger number of second tributary channels 622 can be provided in second main channel 612. Similarly, a larger number of third tributary channels 623 can be provided in third main channel 613, and a larger number of fourth tributary channels 624 can be provided in third main channel 613. Therefore, the contact area with the refrigerant in storage chamber 6 can be increased, and the efficiency of heat transfer to the refrigerant by heat exchangers 4A2-4A9 can be improved.

[0072] Each of the heat exchangers 4A2 to 4A9 includes a plurality of first tributary channels 631 and a plurality of second tributary channels 632. The cross-sectional area of ​​each of the plurality of first tributary channels 631 is smaller than the cross-sectional area of ​​the first tributary channel 621 and the cross-sectional area of ​​the third tributary channel 623. The plurality of first tributary channels 631 include a channel that connects the first tributary channel 621 and the third tributary channel 623. The cross-sectional area of ​​each of the plurality of second tributary channels 632 is smaller than the cross-sectional area of ​​the second tributary channel 622 and the cross-sectional area of ​​the fourth tributary channel 624. The plurality of second tributary channels 632 includes a channel that connects the second tributary channel 622 and the fourth tributary channel 624. This configuration increases the surface area of ​​the flow path throughout the entire accommodating chamber 6, thereby increasing the contact area with the refrigerant in the accommodating chamber 6 and suppressing an increase in pressure loss, thereby improving the efficiency of heat transfer to the refrigerant by the heat exchangers 4A2 to 4A9.

[0073] In heat exchangers 4A2 to 4A9, the first target side along which the first main flow path 611 runs is the first side 51 when half the length of the first side 51 is greater than the length of the third side 53, the third side 53 when half the length of the first side 51 is less than the length of the third side 53, and at least one of the first side 51 and the third side 53 when half the length of the first side 51 and the length of the third side 53 are equal. The second target side along which the second main flow path 612 runs is the first side 51 if half the length of the first side 51 is greater than the length of the fourth side 54, is the fourth side 54 if half the length of the first side 51 is less than the length of the fourth side 54, and is at least one of the first side 51 and the fourth side 54 if half the length of the first side 51 and the length of the fourth side 54 are equal. According to this configuration, the first main flow path 611 can be made to extend linearly and long within the storage chamber 6, and the second main flow path 612 can be made to extend linearly and long within the storage chamber 6. This reduces the flow path resistance of the first main flow path 611 and the flow path resistance of the second main flow path 612, thereby preventing an increase in pressure loss of the refrigerant. This increases the efficiency of heat transfer to the refrigerant by the heat exchangers 4A2 to 4A9.

[0074] In heat exchangers 4A2 to 4A9, the first flow port 55 may be positioned away from the center 51C of the first side surface 51 toward the third side surface 53 by a length of 0.75 or more and 1 or less, where 1 is the length from the center 51C of the first side surface 51 to the third side surface 53. In addition, in heat exchangers 4A2 to 4A9, the second flow port 56 may be positioned away from the center 51C of the first side surface 51 toward the fourth side surface 54 by a length of 0.75 or more and 1 or less, where 1 is the length from the center 51C of the first side surface 51 to the fourth side surface 54. According to this configuration, the first main flow path 611 and the second main flow path 612 can each extend in a substantially straight line, thereby reducing the flow path resistance of each of the main flow paths 611, 612 and further increasing the contact area with the refrigerant in the storage chamber 6. Furthermore, even if the first circulation port 55 and the second circulation port 56 are arranged at the above positions, by setting the aspect ratio of the storage chamber 6 to be 0.6 or more and 10.0 or less, the refrigerant can be more easily circulated throughout the storage chamber 6 efficiently, and the pressure loss of the refrigerant can be further reduced. Therefore, the efficiency of heat transfer to the refrigerant by the heat exchangers 4A2 to 4A9 can be further improved.

[0075] [Second embodiment] Next, a second embodiment of the present disclosure will be described. The projector according to this embodiment has a similar configuration to the projector 1 according to the first embodiment, but differs in the configuration of the heat exchanger that constitutes the cooling device 3. More specifically, the heat exchanger for the gas in this embodiment further includes a fourth circulation port and a fourth main flow path. Note that in the following explanation, parts that are the same or approximately the same as parts already explained will be assigned the same reference numerals and explanations thereof will be omitted.

[0076] [Projector configuration] Fig. 18 is a cross-sectional view showing the internal configuration of a heat exchanger 7 included in a cooling device of a projector according to this embodiment. Specifically, Fig. 18 is a cross-sectional view showing the internal configuration of a heat exchanger 71 of the heat exchanger 7, which includes: a first circulation port 55 located 0.75 away from the center 51C of the first side surface 51 toward the third side surface 53 when the distance from the center 51C to the third side surface 53 is defined as 1; a second circulation port 56 located 0.75 away from the center 51C toward the fourth side surface 54 when the distance from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1; a third circulation port 57; and a fourth circulation port 58 located at the center 51C of the first side surface 51, and in which the aspect ratio of the storage chamber 6 is 2.25. In Fig. 18, only some of the multiple first tributary channels 621 are denoted by reference numerals. The same applies to the second tributary channel 622, the third tributary channel 623, the fourth tributary channel 624, the first narrow tributary channel 631 and the second narrow tributary channel 632. The projector according to this embodiment has the same configuration and functions as the projector 1 according to the first embodiment, except that it has a heat exchanger 7, an example of which is shown in Fig. 18, instead of the heat exchanger 4. That is, the cooling device according to this embodiment has the same configuration and functions as the cooling device 3 according to the first embodiment, except that it has a heat exchanger 7 instead of the heat exchanger 4. That is, the cooling device according to this embodiment has a plurality of heat exchangers 7. Although not shown in the figures, the plurality of heat exchangers 7 include a red heat exchanger connected to the heat receiving plate 22R so as to be heat transferable, a green heat exchanger connected to the heat receiving plate 22G so as to be heat transferable, and a blue heat exchanger connected to the heat receiving plate 22B so as to be heat transferable.

[0077] [Heat exchanger configuration] Similar to the heat exchanger 4, the heat exchanger 7 is a cold plate that cools the heat-generating element by transferring heat received from the heat-generating element to a refrigerant flowing therethrough. The heat exchanger 7 has the same configuration and function as the heat exchanger 4 according to the first embodiment, except that it further includes a fourth flow port 58 and a fourth main flow path 614. That is, the heat exchanger 7 includes a housing 5 having an accommodating chamber 6 surrounded by a first side surface 51, a second side surface 52, a third side surface 53, and a fourth side surface 54, a first flow port 55, a second flow port 56, a third flow port 57, a fourth flow port 58, a first main flow path 611, a second main flow path 612, a third main flow path 613, a fourth main flow path 614, branch flow paths 621, 622, 623, 624, and narrow branch flow paths 631, 632.

[0078] Although not shown in the figures, in the heat exchanger 7, when the above-mentioned dimensional ratio L2 / L1 is 4.0 or more, the first main flow path 611 extends from the first flow port 55 along the first side surface 51 toward the fourth side surface 54, and also extends along the third side surface 53 toward the second side surface 52. Furthermore, in the heat exchanger 7, when the dimensional ratio L2 / L1 is 4.0 or more, the second main flow path 612 extends from the second flow port 56 along the first side surface 51 toward the third side surface 53, and also extends along the fourth side surface 54 toward the second side surface 52.

[0079] The fourth circulation port 58 is disposed on the first side surface 51 of the housing 5 between the first circulation port 55 and the second circulation port 56. Specifically, the fourth circulation port 58 is disposed at the center 51C of the first side surface 51. The fourth circulation port 58 communicates between the outside of the housing 5 and the inside of the storage chamber 6. The fourth circulation port 58 allows the refrigerant circulating in the cooling device to flow through it. The fourth main flow path 614 communicates with the outside of the housing 5 via the fourth flow port 58. The fourth main flow path 614 extends from the fourth flow port 58 toward the second side surface 52 within the accommodation chamber 6, and communicates with each of the third branch flow path 623 and the fourth branch flow path 624. In the heat exchanger 71 shown in FIG. 18 , which is an example of a heat exchanger, the flow path cross-sectional area of ​​the fourth main flow path 614 is smaller than the flow path cross-sectional area of ​​the third main flow path 613 on the third flow port 57 side.

[0080] In the heat exchanger 71, the third main flow path 613 is made up of a first partial flow path 6131, a second partial flow path 6132, and a third partial flow path 6133. The first partial flow path 6131 communicates with the outside of the housing 5 via the third flow port 57. The first partial flow path 6131 includes first partial flow paths 6131A and 6131B that sandwich the fourth main flow path 614 on the Y axis. The first partial flow path 6131A extends between the first main flow path 611 and the fourth main flow path 614, and the first partial flow path 6131B extends between the second main flow path 612 and the fourth main flow path 614. The flow path cross-sectional area of ​​each of the partial flow paths 6131A and 6131B decreases with increasing distance from the third flow port 57. The second partial flow path 6132 is a flow path through which a coolant can flow, extending from the first partial flow path 6131A along the second side surface 52 toward the third side surface 53. The flow path cross-sectional area of ​​the second partial flow path 6132 becomes smaller toward the first side surface 51. The third partial flow path 6133 is a flow path through which a refrigerant can flow, extending from the first partial flow path 6131B along the second side surface 52 toward the fourth side surface 54. The flow path cross-sectional area of ​​the third partial flow path 6133 becomes smaller toward the first side surface 51.

[0081] [Refrigerant circulation path in the storage chamber] In such a heat exchanger 71, when the flow ports 55, 56, and 58 are used as refrigerant inlet ports and the flow port 57 is used as a refrigerant outlet port, the refrigerant flows through the first main flow path 611, the second main flow path 612, and the fourth main flow path 614. The refrigerant that has circulated through the first main channel 611 circulates through at least one of the first branch channel 621, the first narrow branch channel 631, and the third branch channel 623 to the first partial channel 6131A or the second partial channel 6132 of the third main channel 613. The refrigerant that has circulated through the second main flow path 612 flows through at least one of the second branch flow path 622, the second narrow branch flow path 632, and the fourth branch flow path 624 to the first partial flow path 6131B or the third partial flow path 6133 of the third main flow path 613. The refrigerant that flows through the fourth main flow path 614 flows through the third branch flow path 623 and the first narrow branch flow path 631 to the first partial flow path 6131A, and also flows through the fourth branch flow path 624 and the second narrow branch flow path 632 to the first partial flow path 6131B. In this way, by having the refrigerant flow through the multiple tributary channels and multiple narrow tributary channels formed within the storage chamber 6, the heat transferred to the heat exchanger 7, including the heat exchanger 71, can be more easily transferred to the refrigerant. If the flow port 57 is used as an inlet for the refrigerant and the flow ports 55, 56, 58 are used as outlets for the refrigerant, the refrigerant will flow in the opposite direction to the above.

[0082] [Heat exchanger heat transfer efficiency] Similar to the heat exchanger 4 according to the first embodiment, a heat exchanger can be configured in which the distances from the center 51C of the first side surface 51 to the first circulation ports 55 and the second circulation ports 56 are different. For example, the heat exchanger 71 shown in Figure 18 is a heat exchanger 71 having a first circulation port 55 located at a position 0.75 away from the center 51C toward the third side surface 53 when the distance from the center 51C of the first side surface 51 to the third side surface 53 is 1, a second circulation port 56 located at a position 0.75 away from the center 51C toward the fourth side surface 54 when the distance from the center 51C of the first side surface 51 to the fourth side surface 54 is 1, and a fourth circulation port 58 located at the center 51C of the first side surface 51.

[0083] FIG. 19 is a graph showing the efficiency of heat transfer to the refrigerant by the heat exchanger 7 with the flow ports 55, 56 positioned differently. Even in the heat exchanger 7 having the flow ports 55 to 58, the efficiency of heat transfer to the refrigerant changes depending on the positions of the first flow port 55 and the second flow port 56 on the first side surface 51. The inventors of the present disclosure investigated the heat transfer efficiency to the refrigerant using heat exchangers 7 in which the distances of first flow ports 55 and second flow ports 56 from center 51C of first side surface 51 were varied, similar to the heat exchangers 41 to 45 described above. As a result, as shown in Fig. 19 , it was found that in heat exchangers 7 in which first flow ports 55 and second flow ports 56 were arranged at positions that were 0.5 to 1 degree away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant was relatively high, whereas in heat exchangers 7 in which first flow ports 55 and second flow ports 56 were arranged at positions that were 0 to less than 0.5 degree away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant was relatively low. It was also found that the heat transfer efficiency to the refrigerant by the heat exchanger 7 in which the flow ports 55, 56 are arranged at a position that is 0.75 or more and 1 or less in length from the center 51C of the first side surface 51 is even higher than the heat transfer efficiency to the refrigerant by the other heat exchangers 7, and that the heat transfer efficiency to the refrigerant by the heat exchanger 71 in which the flow ports 55, 56 are arranged at a position that is 0.75 in length from the center 51C of the first side surface 51 is the highest.

[0084] For the above reasons, the cooling device according to this embodiment preferably employs a heat exchanger 7 having a first flow port 55 disposed at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, where 1 is the length from the center 51C of the first side surface 51 to the third side surface 53, and a second flow port 56 disposed at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54, where 1 is the length from the center 51C of the first side surface 51 to the fourth side surface 54. Furthermore, the cooling device according to this embodiment preferably employs a heat exchanger 7 having a first flow port 55 disposed at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, and a second flow port 56 disposed at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54.

[0085] Fig. 20 is a graph showing the heat transfer efficiency to the refrigerant by heat exchangers 7 with different dimensional ratios L2 / L1. Note that the graph shown in Fig. 20 shows the heat transfer efficiency to the refrigerant by each heat exchanger 7, with the heat transfer efficiency of the heat exchanger 4A4, which has the highest heat transfer efficiency among the heat exchangers 4A according to the first embodiment, set at 100%. Even in the heat exchanger 7 having the flow ports 55 to 58, the efficiency of heat transfer to the refrigerant changes depending on the aspect ratio, ie, the dimension ratio L2 / L1. The inventors of the present disclosure investigated the heat transfer efficiency to the refrigerant using heat exchangers 7 having different dimensional ratios L2 / L1 of the length L2 of the storage chamber 6 along the first side surface 51 to the length L1 of the storage chamber 6 along the third side surface 53, similar to the heat exchangers 4A1 to 4A10 described above. As a result, as shown in Fig. 20, it was found that the heat transfer efficiency to the refrigerant of heat exchangers 7 having a dimensional ratio L2 / L1 of 0.6 or more and 10.0 or less was higher than the heat transfer efficiency to the refrigerant of heat exchangers 7 having a dimensional ratio L2 / L1 of less than 0.6 and the heat transfer efficiency to the refrigerant of heat exchangers 7 having a dimensional ratio L2 / L1 of more than 10.0. It was also found that the heat transfer efficiency to the refrigerant by heat exchangers 7 having a dimension ratio L2 / L1 of 1.0 or more and 10.0 or less is higher than the heat transfer efficiency to the refrigerant by other heat exchangers 7, and that the heat transfer efficiency to the refrigerant by heat exchangers 7 having a dimension ratio L2 / L1 of 1.0 or more and 4.0 or less is even higher than the heat transfer efficiency to the refrigerant by other heat exchangers 7. For this reason, it is preferable to use a heat exchanger 7 in which the dimensional ratio L2 / L1 is 0.6 or more and 10.0 or less for the cooling device of this embodiment, it is more preferable to use a heat exchanger 7 in which the dimensional ratio L2 / L1 is 1.0 or more and 10.0 or less, and it is even more preferable to use a heat exchanger 7 in which the dimensional ratio L2 / L1 is 1.0 or more and 4.0 or less.

[0086] [Effects of the second embodiment] The projector according to this embodiment described above has the same effects as the projector 1 according to the first embodiment, and also has the following effects. Heat exchanger 7, in which the dimensional ratio L2 / L1 is 0.6 or more and 10.0 or less, includes, in addition to the configuration of heat exchangers 4A2 to 4A9, a fourth flow port 58 and a fourth main flow path 614. Fourth flow port 58 is disposed at center 51C of first side surface 51, and connects the outside of housing 5 with the inside of accommodation chamber 6. A refrigerant can flow through fourth flow port 58. The fourth main flow path 614 extends from the fourth flow port 58 toward the second side surface 52 and communicates with each of the third branch flow path 623 and the fourth branch flow path 624. In this embodiment, the flow path cross-sectional area of ​​the fourth main flow path 614 is smaller than the flow path cross-sectional area of ​​the third main flow path 613 on the third flow port 57 side. This configuration can increase the flow rate of the refrigerant circulating in the heat exchanger 7. Therefore, it is possible to improve the efficiency of heat transfer to the refrigerant by the heat exchanger 7. Note that, because the cross-sectional area of ​​the fourth main flow path 614 extending from the fourth flow port 58 is smaller than the cross-sectional area of ​​the third main flow path 613, it is possible to increase the surface area of ​​the flow path over the entire storage chamber 6, and therefore the contact area with the refrigerant in the storage chamber 6 can be expanded.

[0087] In the heat exchanger 7 in which the dimensional ratio L2 / L1 is 0.6 or more and 10.0 or less, the third main flow path 613 includes a first partial flow path 6131, a second partial flow path 6132, and a third partial flow path 6133. The first partial flow path 6131 communicates with the outside of the housing 5 via the third flow port 57 . The second partial flow path 6132 extends from the first partial flow path 6131 toward the third side surface 53 . The third partial flow path 6133 extends from the first partial flow path 6131 toward the fourth side surface 54 . With this configuration, the refrigerant can circulate between the first main flow path 611 and the fourth main flow path 614 and the third main flow path 613, and also between the second main flow path 612 and the fourth main flow path 614 and the third main flow path 613. Therefore, when one of the first flow port 55, the second flow port 56, the fourth flow port 58, and the third flow port 57 is an inlet for introducing the refrigerant into the storage chamber 6 and the other is an outlet for discharging the refrigerant that has circulated within the storage chamber 6, the refrigerant can be easily circulated within the storage chamber 6. Therefore, the efficiency of heat transfer to the refrigerant by the heat exchanger 7 can be improved.

[0088] [Modification of the embodiment] The present disclosure is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present disclosure are included in the present disclosure. In the first embodiment, for example, the heat exchangers 4A2 to 4A9 having the dimension ratio L2 / L1 of 0.6 or more and 10.0 or less have the first flow port 55 and the second flow port 56 provided in the first side surface 51 and one third flow port 57 provided in the second side surface 52. In the second embodiment, the heat exchanger 7 having the dimension ratio L2 / L1 of 0.6 or more and 10.0 or less has the first flow port 55, the second flow port 56, and the fourth flow port 58 provided in the first side surface 51 and the third flow port 57 provided in the second side surface 52. However, the number of flow ports provided in the first side surface 51 may be four or more, and the number of flow ports provided in the second side surface 52 may be two or more.

[0089] In each of the above embodiments, the storage chamber 6 is formed in a rectangular shape surrounded by the side surfaces 51 to 54 when viewed from the ±Z direction. However, the storage chamber 6 is not limited to this, and may be formed in another polygonal shape when viewed from the ±Z direction, or may be formed in a circular shape including an ellipse.

[0090] In each of the above embodiments, the storage chamber 6 is configured to be line-symmetrical about an imaginary straight line that passes through the center 51C of the first side surface 51 and is perpendicular to the first side surface 51. However, this is not limited thereto, and the arrangement of the flow paths 611-614, 621-624, 631, 632 in the region of the storage chamber 6 on the third side surface 53 side from the imaginary straight line and the region of the storage chamber 6 on the fourth side surface 54 side from the imaginary straight line does not have to be line-symmetrical about the imaginary straight line.

[0091] In each of the above embodiments, the third flow port 57 is arranged at the center 52C of the second side surface 52 in the Y axis direction. However, this is not limiting, and the third flow port 57 may be shifted from the center 52C on the second side surface 52 toward the third side surface 53 or the fourth side surface 54. Furthermore, the third main flow path 613 connected to the third flow port 57 may be arranged so as to be biased toward the third side surface 53 or the fourth side surface 54.

[0092] In each of the above-described embodiments, for example, the heat exchangers 4A2 to 4A9, 7 in which the dimensional ratio L2 / L1 is equal to or greater than 0.6 and equal to or less than 10.0 include a plurality of first small tributary channels 631 and a plurality of second small tributary channels 632. However, this is not limiting, and at least one of the first small tributary channels 631 and the second small tributary channels 632 may be omitted. Furthermore, the plurality of first narrow tributary channels 631 include a channel that connects the first tributary channel 621 and the third tributary channel 623. However, this is not limiting, and each of the plurality of first narrow tributary channels 631 provided in the first tributary channel 621 may be connected to the third main channel 613, and each of the plurality of first narrow tributary channels 631 provided in the third tributary channel 623 may be connected to the first main channel 611. The same applies to the second narrow tributary channels 632.

[0093] In the first embodiment described above, the first target side surface along which the first main flow channel 611 extends is determined based on a comparison result between half the length of the first side surface 51 along the Y axis and the length of the third side surface 53 along the X axis, and the second target side surface along which the second main flow channel 612 extends is determined based on a comparison result between half the length of the first side surface 51 along the Y axis and the length of the fourth side surface 54 along the X axis. However, this is not limiting, and the extension directions of the first main flow channel 611 and the second main flow channel 612 may be determined based on a predetermined mathematical formula.

[0094] In each of the above-described embodiments, the cooling device 3 includes the heat exchangers 4A2 to 4A9, 7, the reservoir 31, the radiator 32, the pump 33, and the piping 34, each having the dimension ratio L2 / L1 of 0.6 or more and 10.0 or less. However, this is not limiting, and the reservoir 31 may be omitted, and the configuration of the cooling device of the present disclosure is not limited to the above. In addition, in each of the above embodiments, the refrigerant flowing through the heat exchangers 4A2 to 4A9, 7 having the dimensional ratio L2 / L1 of 0.6 or more and 10.0 or less is a liquid refrigerant, but this is not limitative and the refrigerant may be a gaseous refrigerant.

[0095] In the first embodiment, the cooling device 3 includes the red heat exchanger 4R, the green heat exchanger 4G, and the blue heat exchanger 4B. However, the number of heat exchangers included in the cooling device 3 is not limited to this and can be changed as appropriate. The same applies to the cooling device according to the second embodiment. In the first embodiment, the refrigerant discharged from the pump 33 flows through the blue heat exchanger 4B, the green heat exchanger 4G, and the red heat exchanger 4R in this order. However, this is not limiting, and the flow order of the refrigerant through the multiple heat exchangers can be changed as appropriate. Furthermore, the refrigerant discharged from the pump 33 may be divided by the pipe 34 and flow in parallel through the blue heat exchanger 4B, the green heat exchanger 4G, and the red heat exchanger 4R. The same applies to the cooling device according to the second embodiment.

[0096] In the above-described embodiments, the heat exchangers 4A2 to 4A9, 7, each having the dimension ratio L2 / L1 of 0.6 or more and 10.0 or less, are connected to the heat receiving plate 22, which is connected to the light source 21, which is a heat generating element, in a heat transferable manner. That is, the heat exchangers according to the above-described embodiments are intended to cool the light source 21, which is a heat generating element. However, this is not a limitation, and the heat receiving plate 22 may be connected to another heat generating element, and the heat exchanger may be cooled by the other heat generating element. For example, the heat receiving plate 22 may be provided on the light modulation element 23, and the heat exchanger may be connected to the heat receiving plate 22 provided on the light modulation element 23 in a heat transferable manner. Furthermore, depending on the configuration of the heat generating element to be cooled, the heat receiving plate 22 may be omitted.

[0097] In each of the above embodiments, the projector 1 includes three light modulation elements 23R, 23G, and 23B. However, the present disclosure is not limited to this and can also be applied to a projector including two or less light modulation elements, or four or more light modulation elements.

[0098] In each of the above embodiments, the light modulation element 23 includes a transmissive liquid crystal panel having different light incident and light exit surfaces. However, the present invention is not limited to this, and the light modulation element may include a reflective liquid crystal panel having the same light incident and light exit surfaces. Furthermore, as long as the light modulation device is capable of modulating an incident light beam to form an image according to image information, a light modulation element other than a liquid crystal may be used, such as a device using a micromirror, for example, a DMD (Digital Micromirror Device).

[0099] In each of the above embodiments, light source 21 includes red light source 21R, green light source 21G, and blue light source 21B, and each of light sources 21R, 21G, and 21B includes a light-emitting element. However, the present invention is not limited to this. Light source 21 may include a light-emitting element and a wavelength conversion element that converts the wavelength of light emitted from the light-emitting element, or may include a discharge light source lamp such as an ultra-high pressure mercury lamp. In other words, the configuration of the light source is not limited.

[0100] In the above-described embodiments, an example was given in which the cooling device 3 including the heat exchangers 4A2 to 4A9, 7 was applied to a projector. However, the present disclosure is not limited to this, and the cooling device including the heat exchangers 4A2 to 4A9, 7 may also be applied to electronic devices other than projectors. For example, the heat exchanger of the present disclosure may be used to cool an integrated circuit included in an electronic device. Furthermore, the heat exchangers 4A2 to 4A9 and the heat exchanger 7 in which the first circulation port 55 and the second circulation port 56 are disposed at positions spaced apart from the center 51C of the first side surface 51 by a distance of 0.5 to 1 and inclusive, and in which the dimensional ratio L2 / L1 is 0.6 to 10.0, may be used in devices other than cooling devices.

[0101] Summary of this disclosure A summary of this disclosure is provided below. [Appendix 1] a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect with the first side surface and the second side surface and are located opposite to each other, and a storage chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first flow port that is arranged in the first side surface in a range from halfway along a length from a center of the first side surface to the third side surface to the third side surface, and through which a refrigerant can flow; a second flow port that is disposed in the first side surface in a range from halfway along a length from a center of the first side surface to the fourth side surface to the fourth side surface, and through which a refrigerant can flow; a third flow port disposed on the second side surface and through which a refrigerant can flow; a first main flow path that communicates with the outside of the housing through the first flow port and extends within the accommodation chamber along a first target side surface that is one of the first side surface and the third side surface; a second main flow path that communicates with the outside of the housing through the second flow port and extends within the accommodation chamber along a second target side surface that is one of the first side surface and the fourth side surface; a third main flow path that communicates with the outside of the housing via the third flow port and extends along one of the first main flow path and the second main flow path within the accommodation chamber; a plurality of first branch channels provided at a plurality of locations on the first main channel and branching off from the first main channel; a plurality of second branch channels provided at a plurality of locations on the second main channel and branching from the second main channel; a plurality of third tributary channels provided in a portion of the third main channel on the side of the first main channel, the third tributary channels communicating with at least one of the plurality of first tributary channels; a fourth branch flow path provided in a plurality of portions of the third main flow path on the second main flow path side, the fourth branch flow path being in communication with at least one second branch flow path among the plurality of second branch flow paths; a dimensional ratio of the length of the storage chamber along the first side surface to the length of the storage chamber along the third side surface is 0.6 or more and 10.0 or less; A heat exchanger characterized by:

[0102] According to this configuration, the first flow port is disposed in the first side surface in a range from halfway along the length from the center of the first side surface to the third side surface, and the second flow port is disposed in the first side surface in a range from halfway along the length from the center of the first side surface to the fourth side surface, which can improve the efficiency of heat transfer to the refrigerant by the heat exchanger, as shown by the results of testing by the inventors of the present disclosure. Furthermore, in the heat exchanger, the dimensional ratio of the length along the first side surface to the length along the third side surface of the accommodation chamber is 0.6 or more and 10.0 or less, thereby making it possible to increase the efficiency of heat transfer to the refrigerant by the heat exchanger compared to when the dimensional ratio is less than 0.6 or exceeds 10.0. Therefore, it is possible to configure a heat exchanger with high efficiency of heat transfer to the refrigerant.

[0103] [Appendix 2] 2. The heat exchanger according to claim 1, a dimensional ratio of the length of the storage chamber along the first side surface to the length of the storage chamber along the third side surface is 1.0 or more and 4.0 or less; A heat exchanger characterized by: This configuration allows the refrigerant to circulate efficiently throughout the entire chamber, and further reduces pressure loss of the refrigerant, thereby further improving the efficiency of heat transfer to the refrigerant by the heat exchanger.

[0104] [Appendix 3] 10. The heat exchanger according to claim 1, wherein: The storage chamber is configured to have a rectangular shape when viewed from a first direction perpendicular to the first side surface and a second direction perpendicular to the third side surface. A heat exchanger characterized by: This configuration allows the refrigerant to circulate throughout the entire chamber, and facilitates the refrigerant to flow from one of the first and second outlets to the other of the third outlet, thereby further improving the efficiency of heat transfer to the refrigerant by the heat exchanger.

[0105] [Appendix 4] 4. The heat exchanger according to claim 3, The storage chamber is configured to be line-symmetrical with respect to a virtual straight line that passes through the center of the first side surface and is perpendicular to the first side surface. A heat exchanger characterized by: According to this configuration, the design of the accommodation chamber in which each flow path is provided, and therefore the design of the heat exchanger, can be simplified.

[0106] [Appendix 5] 5. The heat exchanger according to claim 1, a flow path cross-sectional area of ​​the first branch flow path is smaller than a flow path cross-sectional area of ​​the first main flow path, a flow path cross-sectional area of ​​the second branch flow path is smaller than a flow path cross-sectional area of ​​the second main flow path, a flow path cross-sectional area of ​​the third branch flow path and a flow path cross-sectional area of ​​the fourth branch flow path are each smaller than a flow path cross-sectional area of ​​the third main flow path; A heat exchanger characterized by: With this configuration, a larger number of first branch channels can be provided in the first main channel, and a larger number of second branch channels can be provided in the second main channel. Similarly, a larger number of third branch channels can be provided in the third main channel, and a larger number of fourth branch channels can be provided in the third main channel. Therefore, the contact area between the refrigerant and the accommodation chamber can be increased, thereby improving the efficiency of heat transfer to the refrigerant by the heat exchanger.

[0107] [Appendix 6] 6. The heat exchanger according to claim 5, a plurality of first tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the first tributary channel and a cross-sectional area of ​​the third tributary channel; a plurality of second tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the second tributary channel and a cross-sectional area of ​​the fourth tributary channel, the plurality of first tributary channels include a channel that connects the first tributary channel and the third tributary channel; the plurality of second tributary channels include a channel that connects the second tributary channel and the fourth tributary channel; A heat exchanger characterized by: This configuration increases the surface area of ​​the flow path throughout the entire chamber, thereby increasing the contact area between the chamber and the refrigerant and suppressing an increase in pressure loss, thereby improving the efficiency of heat transfer to the refrigerant through the heat exchanger.

[0108] [Appendix 7] 7. The heat exchanger according to claim 1, The first target aspect is If half the length of the first side is greater than the length of the third side, then it is the first side; If half the length of the first side is less than the length of the third side, it is the third side; When half the length of the first side surface is equal to the length of the third side surface, the side surface is at least one of the first side surface and the third side surface, The second target aspect is If half the length of the first side is greater than the length of the fourth side, then it is the first side; If half the length of the first side is less than the length of the fourth side, it is the fourth side; When half the length of the first side surface and the length of the fourth side surface are equal, the side surface is at least one of the first side surface and the fourth side surface. A heat exchanger characterized by: With this configuration, the first main flow path can be made to extend linearly and long within the accommodation chamber, and the second main flow path can be made to extend linearly and long within the accommodation chamber. This reduces the flow path resistance of the first main flow path and the flow path resistance of the second main flow path, thereby preventing an increase in pressure loss of the refrigerant. Therefore, the efficiency of heat transfer to the refrigerant by the heat exchanger can be improved.

[0109] [Appendix 8] 7. The heat exchanger according to claim 1, a fourth flow port disposed at the center of the first side surface and through which a refrigerant can flow; a fourth main flow path that communicates with the outside of the housing through the fourth flow port, extends toward the second side surface within the accommodation chamber, and communicates with each of the third branch flow path and the fourth branch flow path; A heat exchanger characterized by: This configuration increases the flow rate of the refrigerant through the heat exchanger. It also increases the surface area of ​​the flow passage throughout the entire chamber, thereby increasing the contact area between the refrigerant and the heat exchanger. This improves the heat transfer efficiency of the heat exchanger.

[0110] [Appendix 9] 9. The heat exchanger according to claim 8, The third main flow path is a first partial flow path communicating with the outside of the housing via the third flow port; a second partial flow path extending from the first partial flow path toward the third side surface; a third partial flow path extending from the first partial flow path toward the fourth side surface, A heat exchanger characterized by: This configuration allows the refrigerant to flow between the first and fourth main flow paths and the third main flow path, as well as between the second and fourth main flow paths and the third main flow path. Therefore, when one of the first, second, and fourth flow paths and the third flow path is an inlet for introducing the refrigerant into the accommodating chamber and the other is an outlet for discharging the refrigerant that has flowed through the accommodating chamber, the refrigerant can be easily circulated within the accommodating chamber. This increases the efficiency of heat transfer to the refrigerant by the heat exchanger.

[0111] [Appendix 10] 10. The heat exchanger according to any one of claims 1 to 9, the first flow port is disposed away from the center of the first side surface toward the third side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the third side surface, When the length from the center of the first side surface to the fourth side surface is 1, the second flow port is disposed away from the center of the first side surface toward the fourth side surface by a length of 0.75 to 1. A heat exchanger characterized by: With this configuration, the first main flow path and the second main flow path can each extend substantially linearly, which reduces the flow path resistance of each main flow path and further increases the contact area with the refrigerant in the storage chamber, thereby further improving the efficiency of heat transfer to the refrigerant by the heat exchanger.

[0112] [Appendix 11] A heat exchanger according to any one of claims 1 to 10; a radiator that radiates heat received by the refrigerant in the heat exchanger; a pump that circulates the refrigerant between the heat exchanger and the radiator, A cooling device characterized by: With this configuration, it is possible to achieve the same effect as the heat exchanger described above, and to configure a cooling device that has high cooling efficiency for an object to be cooled.

[0113] [Appendix 12] a cooling device according to claim 11; A light source and a light modulation element that modulates the light emitted from the light source; a projection optical device that projects the modulated light; a heat receiving plate provided on one of the heat generating elements of the light source and the light modulation element, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. A projector characterized by: This configuration can improve the cooling efficiency of the heat generating element of either the light source or the image forming panel, thereby suppressing the temperature rise of the heat generating element even when the amount of light incident on the light modulation element from the light source is increased, thereby enabling the construction of a projector capable of projecting high-brightness image light.

[0114] [Appendix 13] a cooling device according to claim 11; a heating element having a heat receiving plate, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. An electronic device characterized by: According to this configuration, the cooling efficiency of the heat generating element can be improved, and therefore an electronic device that can operate stably can be configured. [Explanation of symbols]

[0115] 1...projector, 2...image projection device, 21...light source, 21B...blue light source, 21G...green light source, 21R...red light source, 22, 22B, 22G, 22R...heat receiving plate, 23...light modulation element, 23B...blue light modulation element, 23G...green light modulation element, 23R...red light modulation element, 24...color combining element, 25...projection optical device, 3...cooling device, 31...reservoir, 32...heat radiator, 33...pump, 34...piping, 4A, 4A2, 4A3, 4A4, 4A5, 4A6, 4A7, 4A8, 4A9, 7, 71...heat exchanger, 4B...heat exchanger for blue, 4G...heat exchanger for green, 4R... Red heat exchanger, 5...housing, 51...first side, 51C...center, 52...second side, 52C...center, 53...third side, 54...fourth side, 55...first circulation port, 56...second circulation port, 57...third circulation port, 58...fourth circulation port, 6...storage chamber, 611...first main flow path, 612...second main flow path, 613...third main flow path, 6131...first partial flow path, 6132...second partial flow path, 6133...third partial flow path, 614...fourth main flow path, 621...first branch flow path, 622...second branch flow path, 623...third branch flow path, 624...fourth branch flow path, 631...first small branch flow path, 632...second small branch flow path.

Claims

1. a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect the first side surface and the second side surface and are located opposite to each other, and a storage chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first flow port that is disposed in the first side surface and extends from a halfway point along a length from a center of the first side surface to the third side surface to the third side surface, and through which a refrigerant can flow; a second flow port, which is disposed in the first side surface and extends from a halfway point of the length from the center of the first side surface to the fourth side surface to the fourth side surface, and through which a refrigerant can flow; a third flow port disposed on the second side surface and through which the refrigerant can flow; a first main flow path that communicates with the outside of the housing through the first flow port and extends within the accommodation chamber along a first target side surface that is one of the first side surface and the third side surface; a second main flow path that communicates with the outside of the housing through the second flow port and extends within the accommodation chamber along a second target side surface that is one of the first side surface and the fourth side surface; a third main flow path that communicates with the outside of the housing via the third flow port and extends along one of the first main flow path and the second main flow path within the accommodation chamber; a plurality of first branch channels provided at a plurality of locations on the first main channel and branching from the first main channel; a plurality of second branch channels provided at a plurality of locations on the second main channel and branching from the second main channel; a plurality of third tributary channels provided in a portion of the third main channel on the side of the first main channel, the third tributary channels communicating with at least one of the plurality of first tributary channels; a fourth branch flow path provided in a plurality of portions of the third main flow path on the second main flow path side, the fourth branch flow path being in communication with at least one second branch flow path among the plurality of second branch flow paths; a dimensional ratio of a length of the storage chamber along the first side surface to a length of the storage chamber along the third side surface is 0.6 or more and 10.0 or less; A heat exchanger characterized by:

2. 2. The heat exchanger according to claim 1, a dimensional ratio of a length of the storage chamber along the first side surface to a length of the storage chamber along the third side surface is 1.0 or more and 4.0 or less; A heat exchanger characterized by:

3. 2. The heat exchanger according to claim 1, The storage chamber is configured to have a rectangular shape when viewed from a first direction perpendicular to the first side surface and a second direction perpendicular to the third side surface. A heat exchanger characterized by:

4. 4. The heat exchanger according to claim 3, The storage chamber is configured to be line-symmetrical with respect to a virtual straight line that passes through the center of the first side surface and is perpendicular to the first side surface. A heat exchanger characterized by:

5. The heat exchanger according to any one of claims 1 to 4, a flow path cross-sectional area of ​​the first branch flow path is smaller than a flow path cross-sectional area of ​​the first main flow path, a flow path cross-sectional area of ​​the second branch flow path is smaller than a flow path cross-sectional area of ​​the second main flow path, a flow path cross-sectional area of ​​the third branch flow path and a flow path cross-sectional area of ​​the fourth branch flow path are each smaller than a flow path cross-sectional area of ​​the third main flow path; A heat exchanger characterized by:

6. 6. The heat exchanger according to claim 5, a plurality of first tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the first tributary channel and a cross-sectional area of ​​the third tributary channel; a plurality of second tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the second tributary channel and a cross-sectional area of ​​the fourth tributary channel, the plurality of first tributary channels include a channel that connects the first tributary channel and the third tributary channel; the plurality of second tributary channels include a channel that connects the second tributary channel and the fourth tributary channel; A heat exchanger characterized by:

7. The heat exchanger according to any one of claims 1 to 4, The first target side surface is if half the length of the first side is greater than the length of the third side, then it is the first side; If half the length of the first side is less than the length of the third side, it is the third side; When half the length of the first side surface is equal to the length of the third side surface, the side surface is at least one of the first side surface and the third side surface, The second target side surface is If half the length of the first side is greater than the length of the fourth side, then it is the first side; If half the length of the first side is less than the length of the fourth side, it is the fourth side; When half the length of the first side surface and the length of the fourth side surface are equal, the side surface is at least one of the first side surface and the fourth side surface. A heat exchanger characterized by:

8. The heat exchanger according to any one of claims 1 to 4, a fourth flow port disposed at the center of the first side surface and through which a refrigerant can flow; a fourth main flow path that communicates with the outside of the housing through the fourth flow port, extends toward the second side surface within the accommodation chamber, and communicates with each of the third branch flow path and the fourth branch flow path; A heat exchanger characterized by:

9. 9. The heat exchanger according to claim 8, The third main flow path is a first partial flow path communicating with the outside of the housing via the third flow port; a second partial flow path extending from the first partial flow path toward the third side surface; a third partial flow path extending from the first partial flow path toward the fourth side surface, A heat exchanger characterized by:

10. The heat exchanger according to any one of claims 1 to 4, the first flow port is disposed away from the center of the first side surface toward the third side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the third side surface, the second flow port is disposed away from the center of the first side surface toward the fourth side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the fourth side surface, A heat exchanger characterized by:

11. The heat exchanger according to any one of claims 1 to 4; a radiator that radiates heat received by the refrigerant in the heat exchanger; a pump that circulates the refrigerant between the heat exchanger and the radiator, A cooling device characterized by:

12. A cooling device according to claim 11; A light source and a light modulation element that modulates the light emitted from the light source; a projection optical device that projects the modulated light; a heat receiving plate provided on one of the heat generating elements of the light source and the light modulation element, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. A projector characterized by:

13. A cooling device according to claim 11; a heating element having a heat receiving plate, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. An electronic device characterized by:

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